This invention pertains to a fastener driving tool having improved bearing and guide assemblies. More particularly, the present invention pertains to a fastener-driving tool having non-metal contacting bearing assemblies and an enhanced aligning nosepiece guide assembly.
Fastener driving tools are well known in the art. Such tools are typically powder-actuated or electric-actuated tools for driving fasteners through a surface, such as a metal deck or metal roof. The fasteners that are driven are of a known type that include a shank having a self-tapping, self-driving or self-drilling tip at one end and head integral with the other end of the shank. Typically, a sealing washer is positioned on the shank with an interference fit.
Known fastener-driving tools generally include a driver such as a powder actuated or an electric-actuated driver that is mounted to telescoping tubes. A first tube (upper or outer tube) is stationary relative to the driver and a second (lower or inner tube) telescopes relative to the upper tube. A shaft is mounted to the driver and extends through the tubes. The lower tube telescopes relative to the upper tube to permit movement of the driver shaft relative to a distal end of the lower tube. An end of the shaft includes, for example, a hex or socket-like element to engage the fastener head for driving. The lower tube telescopes to permit movement between a retracted position and a contracted position. In the retracted or extended position, a fastener is loaded onto an end of the shaft for driving into the surface. In the contracted position, the fastener is driven from the tool outwardly, through the distal end of the lower tube, into the surface.
Known fastener driving tools include a spring positioned between the tubes to urge the tubes and thus the tool into the retracted or loading position. In known driving tools, the lower tube is fitted immediately within the upper tube. Although this assures proper alignment of the tubes relative to one another and straight movement of the fastener, there is surface-to-surface contact of the tubes. In that these tubes are formed of metal this produces metal-to-metal contact between the tubes and can result in high frictional forces and possibly binding of the tubes.
Generally, a stop is positioned on the end of the upper tube that cooperates with a stop positioned along the length of the lower tube. This limits that travel of the tubes relative to one another and assures that the fastener is properly driven into the surface. That is, the stops are positioned relative to one another so that the fastener is driven a predetermined amount into the surface.
Known fastener driving tools include a nosepiece assembly that supports the fastener prior to and as it is engaged by the driver shaft (e.g., socket-like element). An opening in the nosepiece provides a track or path through which the fastener is driven from the tool. One drawback to known nosepiece assemblies is that while the nosepiece is relatively large, the opening through which the fastener is driven is relatively small. In that some types of roofing systems have preformed holes for receiving the fasteners, it is only with skill, practice and close inspection that the fastener opening is properly aligned with the roof deck panel hole. Other types of roofing systems require fastening roof panels, without these preformed holes, to one another and/or to underlying structural members.
In addition, many such metal roofing systems are formed having a corrugated profile defined by xe2x80x9cpeaksxe2x80x9d and xe2x80x9cvalleysxe2x80x9d. For those systems that have the preformed holes, the holes are typically formed on the peak portion of the corrugations. This makes it even more difficult to align the tool while maintaining it balanced on top of the corrugation while driving the fastener.
Accordingly, there is a need for a fastener driving tool that has an improved bearing surface to eliminate the problems associated with metal-to-metal sliding tube contact. Desirably, such a tool includes an enhanced fastener aligning and guide assembly to facilitate proper positioning of the fastener over the surface into which the fastener is driven. Most desirably, these enhanced features are provided in a tool that permits the tool operator to use the tool standing in an erect or near-erect stance to reduce operator fatigue.
A fastener driving tool for driving fasteners into a workpiece is for use by an operator in a substantially erect position. The tool is configured for use on roof panels to drive fasteners into the panels for panel to panel and panel to structural applications. The panels have a corrugation-like profile defining a peak, a pair of valleys adjacent to the peak and respective walls extending between the peak and the adjacent valleys. Holes may be pre-formed in the panels, along the peak, for fastening the panels to the underlying structure or for joining panels to one another.
The tool includes a driver, such as an electric motor, telescopic extension members and a fastener receiving member. The telescopic extension members permit driving the fasteners into the roof panel. The fastener receiving member receives a fed fastener, supports the fastener during loading and releases the fastener as it is driven into the roof panel.
The driver has a driver shaft extending therefrom. The first extension member is operably connected to the driver and the second extension member is operably connected to the first extension member. In a current embodiment, the extension members are formed as tubes, with the first tube being a upper tube and the second member being a lower tube. The lower tube slidingly engages the upper tube between a loading position to load fasteners into the tool and a driving position to drive the fasteners from the tool into the roof panels.
A bearing assembly operably connects the upper and lower tubes. The bearing assembly is formed from a non-metallic, low-friction material, such as an acetal resin. A portion of the bearing assembly is mounted to one of the upper and lower tubes for sliding engagement with the other tube. The bearing assembly is positioned to prevent direct contact of the tubes with one another.
In one embodiment, the bearing assembly includes an upper tube bearing mounted to a lower end of the upper tube for slidingly engaging the lower tube. Preferably, the upper tube bearing including a sleeve portion mounted to the upper tube and a bearing portion extending transverse to and inwardly of the sleeve portion for contact with the lower tube.
The bearing assembly can further include a driver shaft guide mounted to the lower tube at about an upper end thereof. The driver shaft guide carries an upper tube bearing surface for slidingly engaging the upper tube. The upper tube bearing surface and the upper tube bearing maintain the upper and lower tubes concentric with one another during use.
The fastener receiving member receives fasteners when in the loading position and supporting and releases the fasteners when in the driving position. The fastener receiving member is mounted to the lower tube. The fastener receiving member includes a cradle having a main body portion and a pair of legs extending from the main body portion diverging downwardly and outwardly from the main body, symmetrical to one another.
The main body defines an upper inside surface extending between and contiguous with the legs, and an opening through the main body portion for passage of the fastener. The cradle is configured for positioning on the panel, straddling the peak with the upper inside surface resting adjacent the peak and the legs extending into the valleys for aligning the opening in the main body portion with a desired location on the roof panel (e.g., the panel hole).
In one embodiment, the cradle includes an aligning member having a jaw assembly that includes first and second jaw pivotal jaw elements mounted thereto. The jaw elements pivot between a closed position wherein the jaw elements abut one another and support a fastener and an open position wherein the jaw elements are pivoted away from one another by the fastener driven therethrough. The jaw elements are mounted to the cradle by pivot pins.
Preferably, an upper guide is mounted to the cradle. The upper guide is movable between a loading position that corresponds to the closed position of the jaw elements and a driving position that corresponds to the open position of the jaw elements. The upper guide includes a locking member for interfering with pivoting of the jaw elements when the upper guide is in the loading position and for disengaging from the jaw elements when the upper guide is in the driving position.
The jaw elements are configured each defining one-half of a cone. When together, the jaw elements define a nadir. In a current embodiment, the nadir extends through the cradle opening beyond the upper inside surface, so that the nadir rests on a desired location (e.g., xe2x80x9cfallsxe2x80x9d into a roof panel hole).
Alternately, the cradle is formed having a viewing opening formed in at least one of the legs. An aligning marker can be formed as a stylus that extends inwardly of the viewing opening or as indicia on the one of the legs.
These and other features and advantages of the present invention will be apparent from the following detailed description, in conjunction with the appended claims.